The invention relates to a headlight lens for a vehicle headlight, in particular for a motor vehicle headlight, as well as to a vehicle headlight.
A headlight lens of that type is e.g. known from U.S. Pat. No. 3,708,221, WO 02/31543 A1, WO 03/074251 A1 and DE 100 52 653 A1. Further types of vehicle headlights are known e.g. from DE 100 33 766 A1, DE 101 18 687 A1 and DE 198 29 586 A1.
DE 203 20 546 U1 discloses a lens blank-moulded on both sides and having a curved surface, a planar surface and a retention edge integrally moulded on the lens edge, wherein a supporting edge of a thickness of at least 0.2 mm and projecting with respect to the planar surface is integrally formed on the retention edge. Herein, the supporting edge is integrally formed on the outer circumference of the headlight lens. A further headlight lens having a supporting edge is disclosed e.g. by DE 10 2004 048 500 A1.
DE 20 2004 005 936 U1 discloses a lens for illuminating purposes, in particular a lens for a headlight for mapping or imaging light emitted from a light source and reflected by a reflector for generating a predetermined illumination pattern, said lens having two surfaces opposing each other, wherein areas of different optical dispersion effects are provided on at least a first surface.
EP 0 969 246 A2 discloses an over-dimensioned lens, wherein the lens grinding and the corresponding projection plane and projection parameter of the reflector mirror are dimensioned such with respect to the lens that only an interior partial area of the lens is used directly. The over-dimensioned edge area merely serves for an optical magnification of the headlight design.
With respect to their optical properties or their photometric standards, headlight lenses are subject to narrow criteria of design. This particularly applies to a light and dark borderline 75, as has been represented, by way of example, in a diagram 70 and a photo 71 in FIG. 9. Herein, the gradient G of the light and dark borderline 75 and the glare value HV of the vehicle headlight into which the headlight lens is installed are important photometric standard values.
It is the object of the invention to reduce the costs in manufacturing a headlight lens for a vehicle headlight, in particular for a motor vehicle headlight, without exceeding photometric standard values.
The aforementioned problem is solved by a method for producing a headlight lens for a vehicle headlight, in particular for a motor vehicle headlight, wherein the headlight lens comprises a lens body made from transparent material and having an essentially planar, optically operative surface and a convexly curved, optically operative surface, wherein, in order to form the headlight lens having an integrally formed lens edge, a pre-form is blank-moulded between a first mould for pressing the convexly curved, optically operative surface and a second mould for pressing the essentially planar, optically effective surface, which second mould comprises a first mould section and an annular second mould section enclosing the first mould section, wherein, by means of an offset depending on the volume of the pre-form, a step is pressed into the headlight lens between the second mould section and the first mould section, and wherein the first mould section is set back with respect to the second mould section at least in the region of the offset.
In particular, it is provided that the essentially planar, optically operative surface is an optically operative surface to be made facing a light source. In particular, it is provided that the convexly curved, optically operative surface is an optically operative surface to be made facing away from a light source. In an advantageous embodiment, the convexly curved, optically operative surface is aspherical.
In the sense of the invention, the transparent material is in particular glass. In the sense of the invention, the term blank-moulding is to mean, in particular, that an optically operative surface is to be pressed such that a subsequent finishing step of the contour of this optically operative surface may be dispensed with or is omitted or is not provided. An integrally formed lens edge, when taken in the sense of the invention, is in particular not to comprise an optically operative surface.
In one embodiment of the invention, the step extends essentially parallel to the optical axis of the headlight lens. In another embodiment, the step is (if necessary additionally) inclined with respect to the optical axis of the headlight lens in the direction of the optical axis.
In a yet further advantageous embodiment of the invention, the distance between the first mould section and the first mould is dependent on the volume of the pre-form. In a further advantageous embodiment of the invention, the distance between the second mould section and the first mould is independent of the volume of the pre-form. In a yet further preferred embodiment of the invention, the second mould section contacts the first mould. In a still further advantageous embodiment of the invention, a contact shoulder is pressed into the lens edge by means of the first mould, wherein the contact shoulder expediently extends essentially orthogonally with respect to the optical axis of the headlight lens.
In a yet further advantageous embodiment of the invention, the essentially planar, optically operative surface projects by no more than 1 mm, advantageously by not more than 0.5 mm beyond the lens edge or a part of the lens edge when seen in the direction of the optical axis of the headlight lens. This in particular means that the height of one step amounts to no more than 1 mm, advantageously no more than 0.5 mm.
In a further expedient embodiment of the invention, the thickness of the lens edge amounts to at least 2 mm. In a yet further advantageous embodiment of the invention, the thickness of the lens edge amounts to no more than 5 mm.
In a still further advantageous embodiment of the invention, the diameter of the headlight lens amounts to at least 40 mm. In a yet further advantageous embodiment of the invention, the diameter of the headlight lens amounts to no more than 100 mm.
In still another advantageous embodiment of the invention, the diameter of the essentially planar, optically operative surface amounts to no more than 110% of the diameter of the convexly curved, optically operative surface. In a still further expedient embodiment of the invention, the diameter of the essentially planar, optically operative surface amounts to at least 90% of the diameter of the convexly curved, optically operative surface.
In one embodiment of the invention, the essentially planar, optically operative surface and/or the convexly curved, optically operative surface is round, in particular circular, or essentially circular.
In a furthermore advantageous embodiment of the invention, the surface of the lens edge or essentially a predominant or at least a predominant or essential portion of the surface of the lens edge extends essentially parallel to the optical axis of the headlight lens along the outer circumference of the lens edge. In this sense, essentially parallel to the optical axis is to mean or is to comprise in particular an inclination of 0° up to 8°, in particular 0° to 5°, with respect to the optical axis.
In one embodiment, the essentially planar, optically operative surface and/or the convexly curved, optically operative surface has a roughness of less than 0.1 .mu.m, in particular less than 0.08 .mu.m, at least in more than one half thereof or essentially in its totality. Roughness in the sense of the invention is in particular to be defined as Ra, in particular according to ISO 4287.
The above-mentioned problem is moreover solved by a method for producing a batch of, in particular, at least sixteen or at least fifty-three headlight lenses for a vehicle headlight, wherein the headlight lenses of the batch are blank-moulded according to the aforementioned process. In an advantageous embodiment of the invention, the batch comprises at least five hundred headlight lenses. In a further advantageous embodiment of the invention, the headlight lenses are placed in a transport container for transporting the headlight lenses. In yet a further expedient embodiment of the invention, the height of one step of a headlight lens of the batch differs by more than 0.05 mm, advantageously by more than 0.1 mm, from the height of a step of a further headlight lens of the batch. In one embodiment of the invention, the step extends essentially parallel to the optical axis of the headlight lens. In a further embodiment, the step is, if necessary additionally, inclined with respect to the optical axis of the headlight lens when seen in the direction of the optical axis.
The above-mentioned problem is moreover solved by a batch of, in particular, at least sixteen or at least fifty-three blank-moulded headlight lenses for vehicle headlights having an integrally moulded lens edge, wherein each one of the headlight lenses of the batch comprises one lens body, each, made of transparent material with an essentially planar, optically operative surface, each, and a convexly curved, optically operative surface, each, wherein the essentially planar, optically operative surfaces project, in the form of a step and when seen in the direction of each optical axis of a headlight lens, beyond the respective lens edge or part of the respective lens edge, and wherein the height of a step of a headlight lens of the batch differs by more than 0.05 mm, advantageously by more than 0.1 mm, from the height of a step of a further headlight lens of the batch. In one embodiment of the invention, the step extends essentially parallel to the optical axis of the headlight lens. In another embodiment, the step is, if necessary in addition, inclined with respect to the optical axis of the headlight lens when seen in the direction of the optical axis.
In an expedient embodiment of the invention, the batch comprises at least five hundred headlight lenses. In a further advantageous embodiment of the invention, the headlight lenses of the batch have one contact shoulder, each, on the lens edge situated on the side of the respective headlight lenses facing away from the step, wherein the contact shoulder advantageously extends essentially orthogonally with respect to the optical axis of the headlight lens.
In a further expedient embodiment of the invention, the essentially planar, optically operative surface projects, when seen in the direction of the optical axis of the headlight lens, beyond the lens edge or part of the lens edge by no more than 1 mm, advantageously by no more than 0.5 mm. This, in particular, means that the height of one step is no more than 1 mm, advantageously no more than 0.5 mm.
In yet a further expedient embodiment of the invention, the thickness of the lens edge is at least 2 mm. In a yet further advantageous embodiment of the invention, the thickness of the lens edge is no more than 5 mm.
In a yet further advantageous embodiment of the invention, the diameter of the headlight lens amounts to at least 40 mm. In a furthermore advantageous embodiment of the invention, the diameter of the headlight lens amounts to no more than 100 mm.
In a still further expedient embodiment of the invention, the diameter of the essentially planar, optically operative surface amounts to no more than 110% of the diameter of the convexly curved, optically operative surface. In a yet further expedient embodiment of the invention, the diameter of the essentially planar, optically operative surface amounts to at least 90% of the diameter of the convexly curved, optically operative surface.
In one embodiment of the invention, the essentially planar, optically operative surface and/or the convexly curved, optically operative surface is round, in particular circular or essentially circular.
In a yet further expedient embodiment of the invention, the surface of the lens edge or at least a predominant or essential part of the surface of the lens edge extends along the outer circumference of the lens edge essentially parallel to the optical axis of the headlight lens. In the sense thereof, “essentially parallel to the optical axis” is to mean or comprise, in particular, an inclination with respect to the optical axis of 0° to 8°, in particular 0° to 5°.
The essentially planar, optically operative surface and/or the convexly curved, optically operative surface in one embodiment has, in more than half thereof or essentially in its totality, a roughness of less than 0.1 .mu.m, in particular of less than 0.08 .mu.m. Roughness, in the sense of the invention, is to be defined, in particular, as Ra, particularly according to ISO 4287.
The aforementioned is moreover solved by a transport container for transporting headlight lenses, wherein a plurality of headlight lenses for vehicle headlights, in particular for motor vehicle headlights, is arranged in the transport container, wherein each one of the headlight lenses of said plurality of headlight lenses comprises a blank-moulded lens body made of transparent material with one essentially planar, optically operative surface, each, and with one convexly curved, optically operative surface, each, and wherein each of the headlight lenses of the plurality of headlight lenses externally comprises one lens edge, each, on their convexly curved, optically operative surfaces, wherein the essentially planar, optically operative surfaces, when seen in the direction of the respective optical axis of a headlight lens, project, in the form of a step, beyond the respective lens edge or a part of the respective lens edge, and wherein the height of one step of a headlight lens of said plurality of headlight lenses differs by more than 0.05 mm, preferably by more than 0.1 mm, from the height of a step of a further headlight lens of said plurality of headlight lenses. In one embodiment of the invention, the step extends essentially parallel to the optical axis of the headlight lens. In another embodiment, the step is, if necessary additionally, inclined with respect to the optical axis of the headlight lens when seen in the direction of the optical axis.
The aforementioned problem is moreover solved by a headlight lens for a vehicle headlight, in particular for a motor vehicle headlight, wherein the headlight lens comprises a blank-moulded lens body made from transparent material and having an essentially planar, optically operative surface and a convexly curved, optically operative surface, and wherein the headlight lens, on the convexly curved, optically operative surface, externally comprises a lens edge, wherein the essentially planar, optically operative surface, when seen in the direction of an optical axis of the headlight lens, projects beyond the lens edge or a part of the lens edge in a stepped manner, and wherein the headlight lens has a contact shoulder on the lens edge on the side of the headlight lens facing away from the step, wherein the contact shoulder advantageously extends essentially orthogonally with respect to the optical axis of the headlight lens, and wherein the essentially planar, optically operative surface advantageously has a roughness of less than 0.1 .mu.m, in particular of less than 0.8 .mu.m. Roughness, in the sense of the invention, is particularly to be defined as Ra, in particular according to ISO 4287.
In one embodiment of the invention, the step extends essentially parallel to the optical axis of the headlight lens. In another embodiment, the step is, if necessary in addition, inclined with respect to the optical axis of the headlight lens when seen in the direction of the optical axis.
In a yet further expedient embodiment of the invention, the essentially planar, optically operative surface projects beyond the lens edge or a part of the lens edge, when seen in the direction of the optical axis, by not more than 1 mm, expediently by not more than 0.5 mm. This, in particular, means that the height of one step amounts to no more than 1 mm, advantageously to no more than 0.5 mm.
In a further expedient embodiment of the invention, the thickness of the lens edge amounts to at least 2 mm. In a further expedient embodiment of the invention, the thickness of the lens edge amounts to no more than 5 mm.
In yet a further advantageous embodiment of the invention, the diameter of the headlight lens amounts to at least 40 mm. In still a further advantageous embodiment of the invention, the diameter of the headlight lens amounts to no more than 100 mm.
In a further advantageous embodiment of the invention, the diameter of the essentially planar, optically operative surface amounts to no more than 110% of the diameter of the convexly curved, optically operative surface. In a yet further advantageous embodiment of the invention, the diameter of the essentially planar, optically operative surface amounts to at least 90% of the diameter of the convexly curved, optically operative surface.
In one embodiment of the invention, the essentially planar, optically operative surface and/or the convexly curved, optically operative surface is round, in particular circular or essentially circular.
In one embodiment, the convexly curved, optically operative surface has, for more than half of it or taken essentially in its totality, a roughness of less than 0.1 .mu.m, in particular of less than 0.8 .mu.m. Roughness, in the sense of the invention, is particularly to be defined as Ra, in particular according to ISO 4287.
The aforementioned problem is furthermore solved by a vehicle headlight, in particular a motor vehicle headlight, having a light source, a shield and a headlight lens in particular comprising one or several of the above-mentioned features, for imaging an edge of the shield as a light and dark borderline, wherein the headlight lens comprises a blank-moulded lens body made from transparent material and having a particularly essentially planar, optically operative surface facing the light source and a particularly convexly curved, optically operative surface facing away from the light source, and wherein the headlight lens, on the optically operative surface facing away from the light source, externally comprises a lens edge, wherein the optically operative surface facing the light source projects beyond the lens edge or a part of the lens edge when seen in the direction of an optical axis of the headlight lens and/or in the direction of the light source, wherein a step is provided between the optically operative surface facing the light source and a surface of the lens edge facing the light source, wherein the headlight lens has a contact shoulder advantageously on the lens edge on the side of the headlight lens facing away from the step, and wherein the essentially planar, optically operative surface advantageously has a roughness of less than 0.1 .mu.m, in particular of less than 0.08 .mu.m. Roughness, in the sense of the invention, is particularly to be defined as Ra, in particular according to ISO 4287. In one embodiment of the invention, the step extends essentially parallel to the optical axis of the headlight lens. In another embodiment, the step is, if necessary additionally, inclined with respect to the optical axis of the headlight lens when seen in the direction of the optical axis.
In an expedient embodiment of the invention, the vehicle headlight is (at least as well) formed as a non-dazzling headlight. In yet a further advantageous embodiment of the invention, the gradient of the light and dark borderline is no more than 0.5. In a yet further advantageous embodiment of the invention, the glare value of the vehicle headlight is no more than 1.5 Lux.
The above-mentioned problem is moreover solved by a vehicle having an aforementioned vehicle headlight, wherein the light and dark borderline may, in an advantageous embodiment of the invention, be imaged on a roadway on which the motor vehicle may be arranged.
The height of the aforementioned steps advantageously amounts to at least 0.1 mm.
It may be provided that an essentially planar, optically operative surface comprises a (concave) curvature having a radius of curvature in the order of 0.5 m.